A Time of Danger : Blind Spot Is a Menace for Surfacing Submarines

Carefully, deliberately and by the book, the crewmen maneuvered the U.S. Navy submarine up from the depths of the Mediterranean Sea. They listened to the sonar for telltale noises. Nothing. The order was given to climb.

As the periscope poked above the surface, the looming image of a 100,000-ton tanker came into focus, dead ahead.

"He was so big that even head-on, bow-on . . . we couldn't hear his screws (propellers) through his hull, so we didn't know he was there," recalled retired Vice Admiral Patrick J. Hannifin. "We came up and went down in a hurry."

Hannifin's submarine escaped harm's way during the near-collision, which occurred more than a decade ago in the Mediterranean Sea. Two weeks ago, off the coast of Los Angeles, the crew of the submarine Houston was not so fortunate. The crew of the tugboat Barcona was less fortunate still.

The nuclear-powered Houston, on standby for filming of the motion picture "The Hunt for Red October," a fictional saga of a Soviet submarine skipper's defection to the United States, snagged the Barcona's steel tow cable and yanked the tugboat backward and under in less than a minute. One crew member drowned and two others survived.

A Navy spokeswoman at the Houston's home port in San Diego called the incident "freakish," but the submarine only two days later, operating in roughly the same waters, sliced through a trawler's fishing net. The Navy says both incidents are under investigation.

Navy officials have left many questions unanswered in the two recent accidents off the Southern California coast involving the Houston, a fast-attack submarine. But evidence has emerged that at least one of the incidents occurred while the Houston was in a blind spot similar to the one described by submarine experts interviewed last week.

Strange as it may seem to civilians, submarine experts say that highly sophisticated Navy submarines sometimes travel through the oceans of the world nearly blind to what is around them. In fact, during some maneuvers the submarine captain operates with a blind spot not unlike a driver changing lanes on a freeway.

Under Navy policy, submarines rarely use the sensitive "active" sonar systems on board because in order to do so they must emit signals that could reveal their location. Instead, they rely on "passive sonar," which means carefully listening for the sound of engines, clanking chains or any other auditory clues.

No Noise, No Detection

But if a vessel is not making any noise, there is little chance that the submariners will detect it.

"It's quite extraordinary," said Angus Peetz, a research aide to George Foulkes, a member of the British Parliament who has pressed for a full-scale investigation of similar sub incidents off the British Isles. "They can hit targets 2,000 miles away, but they can't spot a fishing boat above them."

While the issue of sub collisions is something relatively new to California mariners, it has been a growing controversy in Britain and Ireland. Members of both the British and Irish parliaments are demanding to know what role submarines may have played in the "mysterious" disappearances, sinkings and snaggings of several dozen fishing boats in the Irish Sea, resulting in the loss of more than 100 lives since 1980.

Officials with the U.S. and British navies have said that their submarines have not been involved in fatal incidents in the area. However, officials in both navies have confirmed details of collisions and several snaggings involving submarines and civilian vessels.

The collisions, naval experts say, illustrate a point that remains true today: Surfacing from the deep is a maneuver that challenges even the most experienced skippers with the highest-tech gadgets on board.

Most Vulnerable Time

"It's that time when the submarine is most vulnerable," said Hannifin, who was commander of all U.S. and NATO submarines in the Mediterranean from 1971 to 1973, then went on to become the director of the Joint Chiefs of Staff. "He's really blind. The problem is that a submarine completely submerged can't see anything.

"It can hear, but it can't see. It can hear a fishing boat, for example, if the fishing boat is running its engines. What it can't hear are fishing nets or barges being towed, because barges don't make any noise."

In order to minimize the chances of running into another vessel, submarines generally travel well below the surface. When it is time to ascend, they move swiftly to periscope depth.

"There is a period, truly, of uncertainty as you go through this transition from the deep submerged state to a shallow submerged state, and so you very carefully search around," said Capt. Thomas C. Maloney, retired commanding officer of a nuclear-powered submarine of the same class as the Houston.

"You maneuver the ship to see if there's some target behind you," Maloney said, "and then you very quickly try to bring the ship up so you can look out through the periscope."